Podcast
Questions and Answers
What is the typical range of ballistics ejected during explosive eruptions?
What is the typical range of ballistics ejected during explosive eruptions?
- Less than 100 metres
- A few hundred metres to 5 km (correct)
- Up to 10 km
- 5 km to 20 km
What distinguishes ballistics from other volcanic fragments?
What distinguishes ballistics from other volcanic fragments?
- They only occur during weak eruptions.
- They are primarily small ash particles.
- They are ejected at variable velocity and angle, not entrained in the volcanic plume. (correct)
- They can only be found within the volcanic plume.
What is the term used for fragments of all sizes generated during the fragmentation of magma and lava?
What is the term used for fragments of all sizes generated during the fragmentation of magma and lava?
- Magma clasts
- Tephra clumps
- Pyroclasts (correct)
- Lava fragments
What makes ballistics a primary hazard during volcanic eruptions?
What makes ballistics a primary hazard during volcanic eruptions?
What is the maximum ejection speed that ballistics can reach during an explosive eruption?
What is the maximum ejection speed that ballistics can reach during an explosive eruption?
Describe how the velocity and angle of ejection vary for ballistics during an explosive eruption.
Describe how the velocity and angle of ejection vary for ballistics during an explosive eruption.
Explain what factors can affect the distance ballistics are thrown during an explosive eruption.
Explain what factors can affect the distance ballistics are thrown during an explosive eruption.
Differentiate between ballistics and tephra clasts in terms of size and ejection.
Differentiate between ballistics and tephra clasts in terms of size and ejection.
Identify the types of materials included under the term 'pyroclasts'.
Identify the types of materials included under the term 'pyroclasts'.
What are the potential impacts of ballistic fragments on infrastructure during volcanic eruptions?
What are the potential impacts of ballistic fragments on infrastructure during volcanic eruptions?
Discuss the role of analytical and numerical models in understanding ballistic dispersal.
Discuss the role of analytical and numerical models in understanding ballistic dispersal.
What mechanism prevents ballistics from becoming entrained within the volcanic plume?
What mechanism prevents ballistics from becoming entrained within the volcanic plume?
Analyze how the size of ballistic fragments influences their behavior during and after an eruption.
Analyze how the size of ballistic fragments influences their behavior during and after an eruption.
What is the typical maximum distance that ballistics can be thrown during powerful explosions?
What is the typical maximum distance that ballistics can be thrown during powerful explosions?
How does the kinetic energy of ballistics pose a hazard to people and infrastructure?
How does the kinetic energy of ballistics pose a hazard to people and infrastructure?
What size classification is given to blocks and bombs that exceed 64 mm?
What size classification is given to blocks and bombs that exceed 64 mm?
What occurs to the velocity of ballistics during flight after ejection?
What occurs to the velocity of ballistics during flight after ejection?
In what ways can the dispersion range of pyroclasts vary?
In what ways can the dispersion range of pyroclasts vary?
What is the primary reason ballistics are not typically entrained within the volcanic plume?
What is the primary reason ballistics are not typically entrained within the volcanic plume?
What is the relationship between the size of ballistic fragments and their potential to affect dispersal models?
What is the relationship between the size of ballistic fragments and their potential to affect dispersal models?
What is one key characteristic of pyroclasts regarding their movement during volcanic eruptions?
What is one key characteristic of pyroclasts regarding their movement during volcanic eruptions?
Flashcards
Ballistics definition
Ballistics definition
Fragments of magma and pre-existing rocks ejected during an explosive eruption, following ballistic trajectories.
Ballistic size range
Ballistic size range
Ballistics range from a few centimeters to several meters in diameter.
Ballistic range
Ballistic range
Typically a few hundred meters to 5 kilometers; can exceed 10 km in powerful eruptions.
Ballistic hazard
Ballistic hazard
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Pyroclasts
Pyroclasts
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What are ballistics?
What are ballistics?
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How are ballistics different from other volcanic debris?
How are ballistics different from other volcanic debris?
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Ballistic size
Ballistic size
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Typical ballistic range
Typical ballistic range
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Maximum ballistic range
Maximum ballistic range
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What are pyroclasts?
What are pyroclasts?
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Ballistic velocity
Ballistic velocity
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Ballistics
Ballistics
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Ballistic dispersal
Ballistic dispersal
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Terminal velocity
Terminal velocity
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What are some models used to predict ballistic dispersal?
What are some models used to predict ballistic dispersal?
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Study Notes
Ballistics in Volcanic Eruptions
- Ballistics are fragments of magma and pre-existing rocks ejected during explosive eruptions.
- They travel in ballistic trajectories, not within the volcanic plume.
- Typical range is a few hundred meters to 5 km, but can exceed 10 km in powerful explosions.
- Fragment sizes vary from centimeters to meters.
- Larger fragments (blocks and bombs, >64mm) can be entrained in the plume and travel further.
- Pyroclasts are fragments of all sizes, moving within flows and the atmosphere.
- Models exist to predict the dispersal of ballistics.
Primary Hazards
- High kinetic energy: Ballistics pose a threat to people, structures, and infrastructure upon impact.
- Velocities can exceed 300 m/s, initially, but terminal velocities are typically less than 150 m/s.
- Impact energy is directly related to the size of the fragment.
- Small fragments (0.2-0.6m diameter) during eruptions (VEI 2–3) can be powerful enough to penetrate reinforced concrete (up to 106 joules).
- Fragments can reach temperatures over 1100°C; heat damage can result upon impact.
Secondary Hazards
- Building collapse: Damage from impact or ignition.
- Infrastructure damage: Impacts to roads, power lines etc.
- Fires: Hot fragments may ignite flammable materials (dry vegetation, wood).
- Shock waves: Intense explosions cause shock waves potentially damaging buildings and delicate equipment at significant distances.
- Infrasonic waves: Additional vibrations can also occur from explosions.
Associated Risk Factors
- Volcanic eruptions can unleash ballistics with little warning.
- Tourists and scientists are particularly vulnerable when close to vents.
- A combination of hazard assessment and effective communication is vital for handling the risk.
- Existing metrics for ballistics may not fully reflect the extent of risk, according to previous studies.
- Previous fatal incidents from eruptions totaled 57 (1500-2017), with impact locations typically within 7 kms of the source.
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